Background: The aim of this study was to investigate factors determining postoperative courses, especially focusing on the rebound phenomenon, in adolescent patients with idiopathic genu valgum who underwent temporary hemiepiphysiodesis and implant removal. Methods: We identified and reviewed patients with idiopathic genu valgum treated with temporary hemiepiphysiodesis [using tension-band plates (plate group, PG) or transphyseal screws (screw group, SG)] and followed-up to skeletal maturity. Results: In our cohort [68 patients and their 68 limbs (randomly selected in bilateral cases)], the mean hip-knee-ankle alignment was -5.4 ± 1.8 degrees at the time of temporary hemiepiphysiodesis (negative means valgus), 2.6 ± 2.1 degrees at the time of implant removal, and 0.7 ± 2.6 degrees at the last followup, respectively. Regarding the implants, the correction speed was not significantly different (P = 0.192-0.315) between the PG (total 1.29 ± 0.37 degrees/mo, 0.71 ± 0.23 degrees/mo at distal femur, 0.59 ± 0.16 degrees/mo at proximal tibia, n = 19) and the SG (total 1.22 ± 0.49 degrees/mo, 0.65 ± 0.25 degrees/mo at distal femur, 0.57 ± 0.23 degrees/mo at proximal tibia, n = 49). The magnitude of rebound phenomenon in the PG (4.1 ± 1.9 degrees) was greater (P < 0.001) than that in the SG (1.1 ± 3.1 degrees). The use of plates and faster correction speed, rather than more severe preoperative deformity or greater correction angle, were positively associated with the rebound phenomenon in regression analyses. Among the 68 knees, 1 showed valgus alignment ≥ 5 degrees and 5 showed varus alignment ≥ 5 degrees at the last follow-up. All the 6 cases were observed in the SG. Surgical wound dehiscence was observed in 1 patient in the PG. Conclusions: The use of plates and faster correction speed were positively associated with the rebound phenomenon. Careful attention will be needed with the corresponding conditions for optimal results. Progressive genu varum after transphyseal screw removal, which was observed in this study, should be explored in future research.

Background: Soft tissue laxity around the knee joint has been recognized as a crucial factor affecting correction error during medial open-wedge proximal tibial osteotomy (MOWPTO). Medial laxity in particular, which represents the changes in joint-line convergence angle (JLCA), affects soft tissue correction. Purpose: The purpose of this study was to quantify medial laxity and develop a preoperative planning method that considers medial laxity. Study Design: Cohort study; Level of evidence, 3. Methods: This study retrospectively reviewed 139 knees in 117 patients who underwent navigation-assisted MOWPTO from January 2014 to July 2019 for symptomatic medial compartment osteoarthritis with varus alignment >5°. We compared the results of 2 preoperative planning methods: conventional Miniaci (n = 47) and latent medial laxity reduction (LMLR) (n = 92). We evaluated the incidence of undercorrection, acceptable correction, and overcorrection. The radiologic parameters were analyzed using multiple linear regression with a stepwise selection model to establish an equation for the optimal preoperative planning method. The intraclass correlation coefficients (ICCs) of intraobserver, interobserver, and intermethod reliability were calculated. Results: The Miniaci method showed a higher incidence of overcorrection (55.3%) than the LMLR method (22.8%) at postoperative 6 months ( P = .0006). Multiple linear regression with a stepwise selection model revealed a high correlation coefficient ( R 2 = 0.888) for the following equation: Adjusted planned correction angle = 0.596 + 0.891 × Target correction angle – 0.255 × Δ JLCA valgus. Upon simplification, the following equation showed the highest intermethod ICC value (0.991): Target correction angle – ⅓Δ JLCA valgus, while the Miniaci method showed a relatively low ICC value of 0.875. Conclusion: There was a risk of overcorrection after MOWPTO using the conventional Miniaci method. An equation that considers medial laxity may help during preoperative planning for optimal correction during MOWPTO.

Medial meniscus posterior root tear is a disruptive injury causing significant sequelae. Several techniques to repair and maintain the native function of the medial meniscus have been introduced, but limitations have been reported in terms of their results. In this current note, the authors introduce the arthroscopic transtibial pull-out repair with whip running suture technique, which may not only avoid the potential risk of meniscus cut-through by the suture material but also optimize the reduction of the extruded meniscus. By suturing the posteromedial capsule and peripheral meniscus, more medialization force can be directly applied to the extruded part of the meniscus, and normal hoop tension can be restored.